Well, on toy cars, I've started to leave them on their stands for display. Why? So that I can save those for admiring, and then if I get lucky enough to own one of those cars, I can drive it, while still having a replica to display.
Personally, I think a car should be out doing what it's purpose was. If it's a Prius, then it should be to get you from A to B with good gas milage. If it's a Ferrari it should be enjoyed. Not stuck tethered to the floor until eternity.